In this Thursday, Jan. 26, 2017, photo, containers of Roundup, left, a weed killer is seen on a shelf with other products for sale at a hardware store in Los Angeles. California regulators are taking a pivotal step toward requiring the popular weed killer Roundup to come with a warning label. The state's Office of Environmental Health Hazard Assessment announced Monday, June 26, 2017, that the weed killer's main ingredient, glyphosate, will be listed in July as a chemical known to cause cancer. (AP Photo/Reed Saxon)